3some with my best girlfriend's stepfather and boyfriend

I was visiting my girlfriend after the disco. She was already so tired that she quickly went to bed and her stepmother was already in bed. Her stepfather and his mate came up to me and asked if I wanted to have a threesome. It was crass, but I hadn't had sex for a pair of days and I really wanted to. But what I didn't know was that her stepfather had a MEGA big and thick cock. It almost blew me up. But then I showed them straight away how I am *G They couldn't believe it when I blew and rode their cocks, they couldn't hold back any longer and squirted on my tits. I hope my girlfriend and her stepmother didn't notice, I was moaning a bit. Shouldn't I have done that?